Therasense, Inc. v. Becton, Dickinson and Company (Fed. Cir. 2011) (en banc)
In a 6–1–4 decision, an en banc Federal Circuit has attempted to cure the “plague” of inequitable conduct pleadings by raising the standards for proving that the alleged bad act was material to patentability and that the patentee undertook the alleged bad act with intent to deceive the USPTO. The court has also rejected the sliding scale approach that previously allowed strong evidence of materiality to compensate for weak evidence of intent to deceive (and vice-versa). Finally, the the court held that a finding of inequitable conduct should not immediately render a patent unenforceable. Rather, the court must also “weigh the equities” to determine whether the inequitable conduct warrants the unenforceability remedy.
To prevail on the defense of inequitable conduct, the accused infringer must prove that the applicant misrepresented or omitted material information with the specific intent to deceive the PTO. The accused infringer must prove both elements—intent and materiality—by clear and convincing evidence. If the accused infringer meets its burden, then the district court must weigh the equities to determine whether the applicant’s conduct before the PTO warrants rendering the entire patent unenforceable.
Intent: For the element of intent to deceive the USPTO, the Federal Circuit now demands evidence of a “deliberate decision” to deceive. Focusing on the failure to submit material prior art, the court held that the intent element requires “clear and convincing evidence that the applicant knew of the reference, knew that it was material, and made a deliberate decision to withhold it. . . . Proving that the applicant knew of a reference, should have known of its materiality, and decided not to submit it to the PTO does not prove specific intent to deceive.” When circumstantial evidence is used, intent to deceive must be the “most reasonable inference.”
Materiality: For the element of materiality, the Federal Circuit now demands evidence of “but-for materiality.” In other words, the court must find that, but for the deception, the PTO would not [should not] have allowed the claim. “In making this patentability determination, the court should apply the preponderance of the evidence standard and give claims their broadest reasonable construction.”
Exceptions: As a major exception, the court here held that in cases involving affirmative egregious misconduct, but-for material need not be proven.
Unenforceable: [UPDATED] Even when material and intent are proven, the court held that a patent should only be rendered unenforceable due to inequitable conduct “where the patentee’s misconduct resulted in the unfair benefit of receiving an unwarranted claim.” As in eBay v. MercExchange, this equitable analysis is intended to serve as a substantial requirement that limits the discretion of district courts.